1. Field of the Invention
The present invention relates to an organic light-emitting diode and, more particularly, to an organic light-emitting diode with high color rendering.
2. Description of Related Art
Organic light-emitting diodes (OLEDs) are advantageous in having low weight, thinness (less than 1 mm), high brightness, wide viewing angle, no need for backlight, low energy consumption, short response time, high resolution, low heat emission, shock resistance, low producing cost, good flexibility etc, and therefore have drawn much attention to the research in the related fields.
Reference with FIG. 1, wherein an organic light-emitting diode is shown, which comprises: a substrate 11, an anode 12, a hole injection layer 13, a hole transport layer 14, a light-emitting layer 15, an electron transport layer 16, an electron injection layer 17 and a cathode 18, in which the light-emitting layer 15 is disposed between the hole transport layer 14 and the electron transport layer 16, and the light-emitting layer 15 is mainly used to control the combination of the electrons and the holes as well as the light-emission.
The color rendering index (CRI) or the power or current efficiency of the OLEDs can be improved with the use of the multiple organic layers and emission layers, however it is difficult to improve the color rendering index (CRI) and the power or current efficiency simultaneously in the conventional OLEDs, whereas the multiple organic layers and emission layers may result in complex process steps that may trigger high providing cost. Thus, it is still difficult to develop an OLED having excellent color rendering index and power or current efficiency at the same time, which is able to replace the commonplace fluorescent lamp.
Therefore, it is desirable to provide an improved OLED that can be applied to illumination usage, which has high illumination efficiency and excellent color rendering index (CRI) simultaneously and is able to replace the commonplace fluorescent lamp.